The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor(s), to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A communication channel is a signal path between a transmitter and a receiver, and a signal transmitted via the communication channel may be modified by noise, interference, and/or frequency-dependent attenuation. Frequency-dependent attenuation can introduce distortions into the transmitted signal including inter-symbol interference (ISI) and jitter. The presence of these distortions in the signal can produce errors in the reception of the signal at the receiver.
A communication channel can be implemented using differential signaling. Differential signaling can reduce the effects of some forms of interference, such as common mode noise.
Equalizers including Continuous Time Linear Equalizers (CTLEs) can be used in communication channels in order to compensate for the channel attenuation. A CTLE may be implemented as a differential amplifier with a fixed or programmable frequency dependent degeneration feature. In one example, a programmable frequency dependent degeneration feature is programmed by adjusting one or more resistance and/or capacitance values in the differential amplifier. These resistance and capacitance values may also define a “roll up point” which is the minimum frequency at which the differential amplifier will start to boost the output signal of the differential amplifier. A CTLE may be useful in other types of systems as well.